Bump Steer Gauge - Twin Analogue or Digital Dial Gauge Design
Bump steer, or roll steer is steer of the wheels through suspension movement, unassisted by the driver. Therefore it's generally undesirable as it can make the vehicle unpredictable to drive.
Tracking is a fundamental part of vehicle set up, but the static tracking becomes an inaccurate point to measure if the amount of bump steer when the vehicle is in motion is unknown.
Manufacturing tolerances, accident repair and set up all add to the amount of bump steer that may be present, and hence even with a new car with the design optimised to minimise bump steer it can still be measurable. This should therefore be an integral part to any vehicle set up.
Typical suspension systems such as twin wishbone independent arrangements create changes in track width with suspension movement due to the nature of the design, the links and therefore wheels follow an arc.
Using twin dial gauges allows you to note whether you are measuring changes in track width or changes in bump steer, by noting the difference between each dial gauge.
If one gauge is used, you are unaware as to what the gauge may be reading which leads to incorrect adjustments being made.
Each gauge is supplied with an etched plaque which allows the user to relate the dial gauge spacings and values displayed to the wheel diameter of the car. This provides a useful means to quantify results - in a similar way that tracking can be done.
Hub plates to suit either 4 or 5 stud hubs and a wide range of wheel pcd's are also supplied, with each gauge featuring a level and adjustable feet to set the gauge level.
This can be purchased as part of a set up kit offer with pad levellers, camber and tracking gauges via the offer shop.